Grinding machine



Dec. 15, 1942. A.. RICKENMANN GRINDING MACHINE Filed Aug. 13, 1941 9Sheets-Sheet 3 Dec. 15, 1942. A. RICKENMANN 3 3 GRINDING MACHINE FiledAug. s, 1941 9 Sheets-Sheet 7 A. RICKENMANN GRINDING MACHNE Filed Aug.15, 1941 9 Sheets -Sheet 8 Dec. 15, 1942.

A. RICKENMANN GRINDING MACHINE Filed Aug. 15, 1941 9 Sheets-Sheet 9Patented Dec. 15, 1942 2305390 GRINDING MAonINE Alfred Rickenmann,Zurich, Switzerland, as- Signor to Reishauer-WcrkzeugeAktiengesellschaft, Zurich, Switzerland, a, corporation of SwitzerlandApplication August 13, 1941, Serial No. 406338 In Switzerland July 29,1940 XVII- XVII of Fig. 16, XVIII--XVIII of Fig. 1,

Claims.

This invention relates to grinding machines and in particular tomachines for grinding thread gauges and similar work with internalthreads, with cylindrical suraces and with radial faces.

' The main object of the invention is to provide a grinding machineadapted to grind to the end in a single fixation and without requiringrefixation of the work blank internal threads, cylindrical surfaces andradially disposed planes, such as the faces of shoulders and so on.

Another object of the invention isto provide a thread grinding machinein which the infeed movement of a multi-grooved disc is efiectedautomatically during the rotary movement of the workpiece, the latterperforming at least one complete revolution after the grinding disc hasreached the full depth of thread, the workspindle and the grinding discbeing returned automatically to their initial positions, while each timebetween the said return movements of. the spindle and the grinding discand the new oper- :ating'sequence there is efiected an additional feedof the grinding disc by hand.

A further object of the invention consists in the provision of agrinding machine of the said type by which all the grinding Operationsand not only the methods for producing screw threads may be performedeither by hand or semi-automatically by simple yet efiicient means.

The invention briefiy described consists in the novel combination andarrangements of. parts hereinafter fully described and particularlypoint-ed out inthe append claims.

* In describing the invention in detail reference is to be had to theaccompanying drawings forming part of this specification, wherein likenumerals of reference indicate the corresponding parts throughout theseveral views thereof.

In the drawings:

Fig. 1 is a side elevation of the new grinding machine and Fig. 2 alongitudinal sectional elevation thereof.

Figs. 3 and 4 are cross-sections on the lines III- III and IV-IV of Fig.l.

Fig. 5 is a section taken on line V-V of Fig. 4.

Fig. 6 is a section taken o'n line VI--VI of Fig. 1.

Figs. 7 and 8 are sections on the lines VII-VII and VIII-VIII of Figs. 1and 6 respectively.

Fig. 9 shows the lay-out of the change speed and reversing gear in adiagrammatical manner.

Figs. 10 to are respectively sections on the lines X-X of Fig. l, XI--XIof Fig. 9, XII-XII of Fig. 2, XIII-XIII of Fig. l, XIV-XIV of Fig.

-X Fi 1, XVI-XVI of Fig. 19,

XIX-XIX of Fig. 1, XX-XX of Fig. 1.

Figs. 21, 22 and 23 illustrate in a diagrammati-' cal manner the workingof the grinding disc and Figs. 24' to 27 show the hydraulic mecham'sm indifferent operative positions.

On the base l of the grinding machine a table 3 is slidably mounted onhorizontal ways 2. The table 3 may be reciprocated by different meansaccording to the work to be performed. The table 3 may be operated *byhand by means of a hand wheel !6 (Figs. 1; 3, 12), fixed to a shaft 269,which is rotatably and axially displaceable mounted in the base I. Aspur wheel ZlD keyed to shaft 269 may be brought in engagement with thespur wheel 2'll which drives by an intermediate gear 212 a spur wheel2l3 meshing with a rack HE fast on table 3. The table 3 may bereciprocated further by fluid pressure mechanism comprising a hydrauliccylinder 2 (Figs. 2, 5, 24-27) with piston lll. The cylinder is astenedto base l, the piston rod is attached to a lug 215 of table 3. Thepiston being actuated by pressure fluid, as will be describedhereinafter, reciprocates the table 3. On the latter two dogs [5 areadjustably mounted cooperating with a controlling lever l3, whichcontrols a distributing valve Mi), (Fig. 2) for the pressure liquid. Thevalve !40 reverses the streke of the piston lll and therewith of thetable 3 as soon as one of the dogs !5 strikes against the lever [3 andturns the same. The lever !3 may be turned by hand with the same effectand for the same purpose. Further the table 3 may be brought to itsinitial position by turning a lever 8, (Figs. 1, 18, 26). said lever 8actuates a distributing valve [(39, ill ISS, na (Fig. 2) of the saidfluid pressure mechanism, which allows pressure fluid to enter thecylinder !12 and to press the piston HI to the left,.Fig. 2, as will bedescribed hereinafter.

To position the table 3 in a working position an adjustable stop ll3(Figs. 2, 5) is provided projecting in the path of the lug 215 on table3. The stop 3 is screwed into one end of a bushing 276, the other end ofwhich is screwed onto the threaded end 211 of a shalt 213. The shaft 218which is journalled in the base l may be rotated by the helical gears2l9, 280 and shaft 28! (Figs. 1, 2, 4, 5) by a hand wheel ll' (Fig. 1).

On the table 3 a slide 4 is arranged running on ways of the table 3parallel to the direction of travel of the latter. The slide 4 partakeson the movements of the table 3, the same fluid'pressure mechanism isused to reciprocate the slide 4. Two dogs !4 adjustably mounted on theslide 4 co-operate with the said controlling lever !3 by which the valvepisten !28 of said fluid pressure mechanism is set. The slide 4 may bemoved ndependently of table 3 by means of a lead screw !82 (Figs. 2, 12,13, 14) journalled in the slide 4 and engaging a nut !84 fastened to thetable 3. By turning the lead screw !82 the slide 4 is moved on the table3. To turn the screw !02 a change speed and reversing gearing isprovided by which the said screw !92 and a shaft or work spindle 88(Figs. 2, 13, 14, 15) carrying the work piece. W may be 'otated at apredetermined ratio. The shaft 88 is journalled in a spindlestock 94mounted on the slide 4. The said spindlestock 94 may be turned about avertical axis and may be fixed in any position on the slide 4 to allowthe grinding of tapering surfaces.

On the base a cross-slide 42 (Figs. 1, 2, 6, 7, 8, 12) is arrangedadapted to be moved to and fro at a right angle to the way of the table3 and slide 4 and therewith of the shaft 89 and the axis of rotation ofthe work piece W. The slide 42 carries the grinding disc 58 (Figs. 1, 2,22) by a shaft 21 rotatably mounted in an arm 44 of a bearing block 43(Figs. 6 and 8). In the latter a shaft 48 is journalled connected Withone end to the shaft of an electro-motor and carrying at the other end abelt pulley 45, driving by a belt 41 and a pulley the grinding discshaft 21. The hearing block 43 is adjustably mounted on the slide 42 bymeans of segmental ways 38 (Fig. 8). The grinding disc shaft 21 may bebrought in any angular position with reference to the axis of shaft 88about which the working piece W rotates. If the grinding disc 58 has tocut screw threads in the work piece W, the plane of rotation of the disc58 may be set into the proper angular position, according to the pitchof the screw threads to be produced. To set the bearing block 43 andtherewith the shaft of the grinding disc 58 into the desired position aworm wheel segment 48 is fastened to the block 43 with which segment 40(Figs. 6, 8), a worm 39 is in engagement. The worm 39 is keyed to ashaft journalled in the cross-slide 42 carrying a hand wheel 22. Byturning the wheel 22` (Figs. 8, 12) the grinding disc 50 may be set inangular relation with. reference to the work piece W.

To move the cross-slide 42 to and fro and to produce the crossfeed ofthe grinding disc 58 a nut 58 (Figs. 6, 8) is fastened to slide 42. Withsaid nut 58 the screw threaded portion 52 of a shaft 54 is inengagement, the latter being' journalled in the base 'On the outer endof the shaft 54 a spur wheel 245 (Figs. 6, '7) is keyed, which is drivenby a pinion 244 on shaft 249, carrying the hand wheel !8 (Figs. 1, 6,7). By turning wheel !8 the slide 42 and therewith the grinding disc 58is radially moved With reference to the work piece W.

On the shaft 54 (Figs. 6, 7) an externally screwthreaded sleeve 48 ismounted on which a nut 49 is arranged. If the nut 49 is rotated theshaft 54 will be moved in axial direction The nut 49 is actuated bymeans of an automatic device described hereinafter in detail by whichthe grinding disc 58 is advanced and withdrawn with reference to thework piece W in a predetermined manner. To take up any backlash of theshaft 54 a weight P (Fig. 6) fixed to a chain 286 running over thepulley 261 is attached to the nut 58 on the cross slide 42.

All the movements of the grinding disc 59 and of the workpiece Wnecessary for carrying out the work may be effected by hand or by anautomatic pressure fluid mechanism in the following manner:

On the base an electro-motor M is mounted, the shaft 68 of which iscoupled with a shaft 6! journalled in the gear box 83. On the shaft 6!(Figs. 2, 9, 10), a gear 11 is keyed, and a pinion !62 on the shaft 9!drives by means of a spur wheel !83 an intermediate shaft !64. On thelatte' four gears !85, !88, !61 and !88 are secured. With said gears thespur wheels !15, !18, !11 and !18 resp ectively may be selectivelybrought in engagement, the last said set of four gears being mounted ona sleeve !14 slidably mounted on a key !13 of a shaft !99. On anothersleeve !88 which is slidably mounted on a shaft !82 there are keyed thespur wheels !84, !85, !86, !81 adapted to be brought selectively inengagement with the gears !88, !12, !1! and !18 respectively, which arealso mounted on the shaft !89, The sleeves !14 and !88 are each operatedby a fork !94 and !95 respectively, which are slidably mounted on ashaft !99. Each fork is provided with a rack 88 and with each rackmeshes a pinion 81. The pinions 61 are journalled in the side wall ofcase I, and may be turned by hand by a knob 68 and 69 (Figs. 1 and 9)respectively.

The spur wheel 11 on shaft 6! meshes with a spur wheel 18 attached to aclutch member !9! rotatably mounted on a shaft 13. A second clutchmember !92 is loosely mounted on the same shaft 13, and between themembers !9!,

!92 a male clutch member 1! is arranged sliding on keys and transmittingthe rotations of either member !9! or !92 to the shaft 13. With a spurwheel !98 attached to the clutch member !92 the spurwheel !89 on theshaft !82 is in engagement. By selectively positioning the sets of gears!84 to !81 and !15 to !18 the speed of the shaft 13 may be varied withinwide limits. The male clutch part 1! is shifted by a lever 12, which isactuated by the dogs !4 and !5 and the pressure fluid mechanism.

I"he shaft 13 drives a vertical shaft 18 (Figs. 9, 12, 13) by means ofthe bevel gears 14, 15 and an universal joint !99 By means of anotheruniversal joint 299 (Figs. 12, 13,), said shaft 18 rotates a verticalshaft 2,9l, rotatably mounted in the slide 4 and in the spindlestock 94.The shaft 28! drives by means of a worm 282 a worm wheel 8! looselymounted on the hollow shaft 89 carrying the work piece W (Figs. 2, 14).The aXis of the shaft 28! is in alignment with the axis about which theheadstock 94 may be rotatably adjusted on its bearing 94 (Fig. 13). On akey of the shaft 89 a clutch member 81 (Figs. 2, 14) is slidably mountedadapted to positively connected the worm wheel 8! with the work spindle88.

The clutch 81 isoperated by a fork 2!! (Figs. 14, 15) mounted on a shaft2!!) which traverses the headstock 94 of the slide 4. On the shaft 2!!)of the fork 2! a spurwheel 2!2 is fastened mesh'ng with apinion 2 !3(Figs, 12, 13) keyed on a shaft ZM journalled in a wall of the headstock94. On the shaft 214 a hand lever 9 (Figs. 1, 13) is fastened by meansof which the clutch 81 may be thrown in and out of engagement with theworm wheel 8!. helical gear !42 is fastened meshing with a helical gear4! (Figs. 2, 15). The latter is mounted on a vertical shaft 88journalled in the head stock 94. On the lower end of the shaft 8.6 aspur wheel is keyed with which the spur wheel 83 On the clutch member 81a (Fig's. 12, 13, 14, may be brought in engagement. The wheel 83 isslidably mounted on the shaft 201; it may be shifted thereon by a fork152 (Figs. 12, 13) attached to a bar 21'1, slidably mounted in the headstock 94. The bar 21'1 is provided with a rack 216 with which the pinion215 keyed to shaft 214 is in engagement. By turning the hand lever 9 notonly the clutch member 8'1, but also the gear 83 is displaced. The wheel85 will be automatically thrown out of gear with the gear 83, if theworm wheel 81 is being coupled with the shaft 80 by the clutch member8'1 and vice-versa.

The wheel 83 may be set by the lever 9 to drive the lead-screw 102(Figs. 2, 14) and to shiit therewith the slide 4 with the head stock 94and work spindle 80 relatively to the table 3 and to the grinding disc56. For this purpose the spur wheel 83 is set by lever 9 to 'mesh withthe gear 84, which drives by a train of change speed gears 228, 221,222, 223, 224 (Figs. 2, 14) by means of the worm 225 the worm wheel 26mounted on the screw threaded shaft 102 (Fig. 2). The coupling of theclutch member 8'1 with the worm wheel 81 by lever 9 will bring the gear83 out of engagement with the gear 85. At the same time the said gear 83will engage the spurwheel 84, driving the slide 4 by the gears 220 to226 and the lead screw. The ratio of speed is about 1 to 16 if the shaft80 is driven by the worm wheel 81 or by the gears 141, 142.

By Operating the lever '12 the shafts '16 and 201 change the directionof rotation and therewith the direction of the travel of the slide 4with work spindle 89 and Workpiece W. To actuate the lever '12automatically the fluid pressure device is made use of. The said devicecomprises a cylinder 122 and a piston 121 (Figs. 2, 19, 20) with pistonrod 250. A cross pin 251 on said piston rod 250 engages a slot of thelever 12 (Fig. 9). The piston 121 moving to and fro reverses the clutchmember '1'1 and therewith the direction of travel of the slide 4. Thepiston rod 250 furthermore operates a gearing to reciprocate the crossslide 42.130 feed the grinding disc 50 to and from the workpiece W. Onthe piston rod 250 a double armed lever 56 (Figs. 2, 9) is rockinglymounted. The upper end of lever 56 is connected with the nut 49 (Figs.2, 6, 7) by means of a link x 5'1. The reciprocating piston rod 250oscillates the nut 49 about the shaft 54 moving thereby shaft 54 inaxial direction and the slide 42 accordingly. The infeed of the disc 50is controlled by cam 90 (Figs' 2, 9, 23 to 27). A part only of theperiphery of the cam 90 is formed con'centrically with its axis ofrotation. The lever 56 presses with a nose N against the periphery ofsaid cam 90 owing to 'the pressure existing in the cylinder 122Operating the piston rod 250 and lever 56 is swung out the nose Nforming the pivot of the lever 56. The latter actuates link 5'1 andcauses the infeed of the grinding disc 50. In the automatic grinding ofscrew threads the cam 90 is rotated and efiects a slow inieed movementof the grinding disc into the workpiece W, in any predetermined measurewith respect to the revolutions made by the Workpiece W. The cam 90 isdriven from the shaft '13 by means of the gears 88, 89, 91 and thehelical gears 93 'and 94 (Fig. 9). A coiled spring 55' placed betweenthe lever 56 and the piston rod 250 keeps the nose N of the lever 56 incontact with the cam 90. The spur wheel 91 is slidably mounted on ashaft 92; it may be shifted against the action of a spring 95 (Figs. 911) bymeans of. a fork 96. The fork is fastened to a rod 91 of a piston98, sliding in a cylinder 99. The latter is connected by a pipe 132(Figs. 2, 11, 24-27) to the valve 140 (Figs. 2, 19, 24-27) of thepressure fluid mechanism. The said valve 140 is actuated by a pin 136projecting sidewards on the cam 90. The pin 136 strikes upon rotationoicam against one arm of a double armed lever 134, the other arm of whichbeing connected by a link rod 13'1 to an arm 134 mounted on a shaft 133(F'g, 17). With the arm 134 a helical gear 38 is rigidly connected whichoscillates by intermediate gears 139, 146, 148 the rotary piston 120 ofthe controlling device 158.

The valve devices 120, 140 govern the action of the piston 111,actuating the table 3; and of the piston 121 respectively actuating there- Versing and change speed gear lever 12; and also of the piston 98(Fig, 11) which brings the cam 90 in and out of action. Oil is fed underpressure to the valve 140 by a pump 84 (Fig. 9) through a pipe 123. Inthe pipe 131 a hand operated throttling valve 11 is arranged (Figs. 1,24 to 27), by means of which the flow of the liquid in the pipe 131 andtherewith the speed of table 3 may be regulated.

. The piston 119 of an auxiliary valve 118 may be actuated by a lever 8(Figs. 1, 18, 20). One arm of the shaft carrying lever 8 engages a guidepiece 109 fastened on the rod 11'1 of the piston' 119. If the piston 119is moved to the left (Fig. 2) the pressure fluid enters on the righthand side of the piston 111. The latter then draws the table 3 to theleft (Fig. 2).

, The fluid pressure mechanism comprises the valve piston 128 which isrotatably and axially displaceable mounted in the cylinder 148. Thevalve piston may be set by the controlling lever 13 co-operating with'the dogs 14 and 15 of the slide 4 and the table 3 respectively. Thelever 13 (Figs. 13, 16) is fixed on the shaft 203, which is rotatablymounted in the base 1. On shaft 203 at the lower end thereof a toothedgear 148 is rigidly fastened meshing with a circular rack 150 formed onthe valve piston 120 (Figs. 16, 17). By turning the lever 13 the valvepiston 120 will be moved in axial direction in the cyl-, inder and bydoing so will interconnect ports and pipes leading pressure fluid to thesaid cylinders 118, 122 in 'a manner as described later on. The shaft203 (Fig, 16) carrying the lev'er 13, is axially displaceable androtatably mounted in a sleeve 256 which in turn is slidably mounted in abore 255 of the base 1. The shaft 203 may be displaced in its axialdirection. For this purpose radial pins 258 in the sleeve 256 engage acircular groove in a bushing 25'1 (Fig. 16) of the gear 148 in such amanner that by an axial displacement of sleeve 256 the shaft 203 will bealso displaced too. The sleeve 256 is provided on its outercircumference with a rack 254 with' which meshes a spur gear 253 (Fig.19) rigidly connected to a spur wheel 149 engaging a toothed flange 151of a sleeve 259 rotatably mounted in the base 1. With the sleeve 259hand lever 5 (Figs. 1 and 19) is rigidly connected. By a key 260 in thesleeve 259 the lever 5 rotates the valve piston 120. By turning thehandle 5 (Fig. 19) the shaft 203 is moved in vertical direction and thelever 13may be'brought in or out of cooperation with the dogs 14 or 15of table 3 and slide 4 respectively or into a neutral position. The gear148 is of such a length that in either position the wheel 146 (Fig. 16)will remain in mesh with it.

f As shown in Fig. 20 there is an automatic stop pin 233, engaging anotoh 234 in the piston I2I. spring 232, which tends to keep th'e pin233 in engagement with the notch 234. The pin 233 may be brought out ofengagement by a knob 233 or by a lever 6, which is fast on a pinion 229engaging a circular rack 230 of the stop pin 233.

The pinion 229 is fast on a shaft 221 on which the lever is keyed. Ifpiston l2l moves downwardly (Fig 20) the tooth 233 is pushed backagainst the action of spring 232 until it springs into the recess 234.The piston |2| is held in its middle position and the lever ?2 keeps theclutch members lsi, !92 out of engagement. The shaf t &il isdisconnected from the motor.

The grinding machine as described can be adapted to perform screw threadgrinding as well as any plain cylindrical grinding and the grinding ofradial planes on shouldered work and so To perform the differentoperations the le- Vers 5, 9 and the stops 14, '55 have to be set. Togrind cylindrical faces by actuating simultaneously the table 3 bypressure fluid, the lever is placed in the position A (Fig. 26) and thelever !3 is set at its lower position to co-operate with the dogs lE.The lever 9 is in the position denoted L (Fig. l). The table 3 isautomatically reciprocated. The shaft 80 with the work piece turnscontinuously in the same direction. The clutch 'll is not actuated andremains in its position, the shaft 86 is driven by 'the helical gearsI4i, i42 (Fig. at a comparatively high speed.

Placing lever 5 into position 'B brings the autotmatic feed mechahisminto Zero position. The lever ES is in its neutral position and does notcooperate either with the dogs !4 or the dogs !5. "The pressure fluiddrive of table 3 is interrupted,

and the table has to be moved by hand wheel !6. iPlacing lever e intoposition L the shaft 80 is driven continuously in the same direction.tPlacing lever S into position [I (zero) the shaft :83 is out of gearwith worm wheel BI and helical gears MI, !42.

The pin 233 stands under the action of a only left handed screw threadsare produced with the infeed of disc 50 by hand. By turning lever 5 fromposition "C" into position D the shaft 203 remains at rest and thesleeve 256 is moved only invertical direction. By adjusting thethrottling valve ll the speed of the table 3 may be controlled. A quickreturn movement of the work piece W from the grinding disc 50 may beeffected by turning lever 8 to the left (Fig. 1). The pressure liquid isled to the right of piston lil (Fig. 2) the latter withdraws thereforethe table 3 away from the grinding disc 50.

To grind screw threads or right handed or left handed screw threads bythe automatic feeding of the grinding disc 50, the lever 5 is positionedat C. The lever [3 is thus placed to co-operate with the dogs |4 on theslide 4. The lever 9 is brought into the position G. The worm gear 8! iscoupled with shaft 86 which runs therefore at low speed At the same timethe spur wheel 83 is brought in mesh with ?the spur wheel 84 and thelead spindle !02 is driven by the train of gears 220 to 224. If lever !3is actuated by the dogs 4 the clutch H, 12 is operated and the reversingof the drive is initiated. The slide 4 and therewith the work piece Wmay be removed quickly from the cross slide 42, by means of lever 8,which Controls the valve !89 after the grinding disc 58 has disengagedthe work piece.

To move the grinding disc automatically to and from the work piece andto reciprocate the slide 4 the cam 90 is resorted to. The gear 9| isbrought in engagement with the spur wheel 89 (Fig. 9) so that the cam 90is now rotated. The reversal of the slide 4 is efiected by the pin |36on the cam and the gearing [31, !38, [39, !46 and me.

To grind left handed screw threads the lever 5 is brought into theposition D. The same operations are repeated as with lever 5 in positionC with the exception that lever !3 works in opposite .direction. Withlever 5 in the position D To grind screw threads on the workpiece thelever 9 is brought into position C (Fig. 1). The helical gears 141, !42are brought out of engagement. The worm wheel 8I is now driven by theworm 232. By turning lever 9 into said position the gear 83 is broughtin engagement with the gear 64. The latter drives by the gear train225-226 the lead spindle |02 and advances the slide 4 while the table 3'remains at rest, abutting on the stop I I3. This allows a correctpositioning of the work piece With reference to the disc 50. The numberof rotations of the workspindle and its advance bear a fixed relationdepending on the pitch of the screw threads to be produced and may bevaried by changing the gears 220 to 224. The return movement of theslide 4 is initiated by turning the lever I3 by hand or by having thelever !3 turned by a dog l4, in such a manner that oil under pressurepasses to the left side of piston !21 (Fig. 2). The piston l2| moving tothe right reverses th clutch H, 9, !92 by turning the lever 12 by meansof its piston rod 256. At the same time the lever 56 is moved andtransmitting its movements to the nut 49 it causes the shaft 54 to turnand to withdraw the cross-slide 42 and therewith the grinding disc fromthe Work-piece W. At the end of the return stroke the lever |3 is turnedagain, but in opposite direction. The piston l2l moves backwards and thepin 233 enters the notch of piston I2l. The latter is arrested and inthis position of the piston |2| the clutch 'H is out of engagement witheither clutch part l9l, !92. The slide 4 and the shaft 80 are at rest.To start the work again the lever 6 has to be pressed down, whereby thepin 233 is withdrawr. The lever |3 is turned and the valve piston !20moved. The pressure liquid moves the piston |2l and therewith the lever12 to the right (Fig. 2). The clutch TI, .l9l, |92` is set again for theworking stroke, the cross-slide 42 being fed by lever 56 and nut 49towards the work piece W. The cross slide 42 is advanced towards theworkpiece by turning the wheel I 8. The wheel I& is provided with anindex playing over a dial. The gradation of the dial is preferably suchthat infeeds of .01 millimeter may be read-off easily. The cross-slide42 is returned for about .5 millimeter to its initial position by thenut 49 which is operated by the piston `|2| and lever 56, as explained.

To grind radial faces, for instance, the shoulder R (Fig. 21) the table3 is positioned by the hand wheel |6 and rack Il. The lever 9 is set tobring the gears l4l, !42 in driving engagement with the shaft '16. Thecross-slide 42 is moved by the handwheel !8, a cup-shaped grinding toolbeing used to grind the face R. The table is preferably brought to bearagainst the adjustable stop |l3 and by adjusting said stop li by thehandwheel IT a very fine feed may be given to the table 3 towards thegrinding disc.

Of the various methods for producing screw threads by means of ,profiledgrinding wheels, the

piece W, on which the screw thread is to be produced so that the axialmovement necessitated by the pitch is given consideration.

With the grinding machine described the crossfeed of the grinding wheelto the depth of screw thread may be effected manually and after thegrinding operation has taken place the grinding disc is also withdrawnfrom the workpiece by hand. Also the return of the workpiece into theinitial position is effected by hand.

Now the machine enables screw threads to be produced in a more speedymanner, especially such screw threads which do not run out freely onboth sides of the screw threaded portion of .the workpiece W, but on oneside abut against 'a shoulder R of the workpiece W. When grinding screwthreads close to an abutting shoulder, it is extremely essential thatalso the last thread close to'the shoulder R corresponds completely withthe exact profile and diameter. important at what speed thecross-feeding of the grinding disc occurs during the rotation of theworkpiece W in relation to the circumferential speed of the workpiece W.

The rat of cross-feeding depends very considerably on the material to betreated. It is particularly important that the rate of cross-feeding canbe maintained constant without being dependent on the skill of theoperator attending to the machine.

These requirements are satisfied by making use of the cam 89 to controlthe infeed of the grinding disc 50 by Operating the lever 56. The lever55 rests on the periphery of the cam S!! by the tooth N, as describedabove. The periphery comprises two parts A and B. The gears driving theworkpiece W and the cam 98 are calculated so that the workpiece W makesabout two turns while the *cam 9!) makes one full turn. The cam 36rotates in the direction indicated by the arrow I (Fig. 9).

The grinding disc 58, while th workpiece W rotates, is fed automaticallyto the necessary depth. The tooth N of the lever 55 rides on the portionA of the cam 95 (Fig. 23). The tooth N is forced outwardly and the lever55 is turned accordingly. The lever 56 turns the nut 59 and the disc 50is fed while the work-piece W turns about an angle equal to A' (Fig 22),until the depth Y of the thread has been obtained. Then, during at leastone complete revolution, the screw thread is completely groundcylindrically, the tooth N riding on the part B of the cam se. Theperiod of time of cross-feeding the grinding disc can be made smallerthan, equal toor greater than one revolution of the workpiece. Thisdepends on the ratio of the depth of the screw thread to the corediameter of the material to be treated and on the quality of thegrinding disc and is a matter of ex- It is Very therewith the lever 56to the right (Fig. 9). The lever 56 is pressed against two stops 266 inthe base arranged on both sides of the pivot of lever 56. The latterrotates the nut 49 by link 51 and shifts the cross-slide 42 from theworkpiece W.

By grinding screw threads in the manner described the lever 9 is setinto position G, the lever 8 is turned to the right and lever !3 isturned to the right. There is pressure in the pipes !23, !24, !25, !29and the pressure fluid flows back in the pipes !26, m, i, eee, 13! and!32.

When grinding coarser screw threads a number of revo-lutions of theworkpiece are necessary. When the ends of the screw threads are .free onboth sides, that is if there is no shoulder on the workpiece close tothe end of the screw threaded portion of the workpiece, the Part of thecrossfeeding can be suitably extended, provided that the grinding wheelis made suificiently wide.

The adjustrnent of the depth of cut and the adjustment of the path ofcross-feeding relatively to the duration of the rotation of theworkpiece may be efiected by mechanical or other control members knownper se.

The machine of the present invention may be used for producing bothexternal threads and internal threads as will be obvious from the abovedescription.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a grinding machine, a base, a table slidably mounted on said base,a slide mounted on said table and adapted to be moved relatively theretoparallel to the direction of movement of said table, a headstock mountedon said slide, a work spindle rotatably mounted in said headstock, aprime mover including a change speed gearing mounted within said basefor rotating a substantially Vertical shaft adapted to be coupled withsaid work spindle for rotating the same means for moving said slide andheadstock thereon relatively to said table, a clutch in said headstookfor selectively drivingly connecting said vertical shaft with said workspindle and said slide moving means respectively, manually operablemeans adapted to move said table, a cross slide mounted on said basemovable at a right angle to the path of movement of said table and theslide thereon, a rotary grinding tool on a spindle and an independentpower drive for said spindle mounted on said cross slide, a secondmanually operable means for moving said cross slide, and a fluidpressure mechanism adapted to move said table and said cross slide andto control the speed and direction of feed of said two membersindependently of their respective manually operable means.

2. In a grinding machine as claimed in claim 1, including within saidchange speed gearing a reversing clutch for reversing the rotation ofsaid Vertical shaft, means for Operating said reversing clutch actuatedby said fluid pressure mechanism, said means including a manuallyoperable valve and adjustable dogs on said table and on said slideadapted to automatically operate said valve at the end of theirrespective feeding strokes.

3. In a grinding machine as claimed in claim 1, including within saidchange speed gearing a reversing clutch for reversing the rotation ofsaid vertical shaft, means for Operating said reversing clutch actuatedby said fluid pressure mechanism, said means including a manuallyoperable valve and adjustable dogs on said table and on said slideadapted to automatically operate said valve at the end of theirrespective feeding strokes, said valve being provided With a leveradapted to be moved selectvely into the path of movement of the dogs onsaid table and said slide respectively, Whereby either the movement ofsaid table or said slide is automatically controlled.

4. In a grinding machine, a base, a table slidably mounted on said base,a slide mounted on said table and adapted to be moved relatively theretoparallel to the direction of movement of said table, a headstock mountedon said slide, a Work spindle rotatably mounted in said headstock, aprime mover including a change speed gearing mounted within said basefor rotating a substantially vertical shaft adapted to be coupled withsaid Work spindle for rotating the same, said vertical shaft extendinginto said headstock, means for rotatably adjusting said headstockrelatively to said slide aboutthe axis of rotaticn of said verticalshaft, means for moving said slide and headstock thereon relatively tosaid table, a clutch in said headstock for selectively drivinglyconnecting said vertical shaft With said Work spindle and said slidemoving means respectively, manually operable means adapted to move saidtable, a cross slide mounted on said base movable at a right angle tothe path of movement of said table and the slide thereon, a 'otarygrinding tool on a spindle and an independent power drive for saidspindle mounted on said cross slide, a second manually operable meansfor moving said cross slide, and a fluid pressure mechanism adapted tomove said table and said cross slide and to control the speed anddirection of feed of said two members independently of their respectivemanually operable means.

5. In a grinding machine as claimed in claim 1, in which said fluidpressure mechanism including a manually and automatically operable valveprovided With a selectively rotatable and axially movable piston, a camcontrolling the movement of said cross slide and normally operativelyconnected with said change speed gearing, a fluid operated memberadapted to disconnect said cam from said change speed gearing, a gearingconnected with said pisten and actuated by said cam after the crossslide has completed its feeding stroke for adjusting said piston andthereby causing said fluid operated member to become effective todisconnect said cam from said change speed gearing.

ALFRED RICKENMANN.

